218 research outputs found
Anomalous thermal expansion and strong damping of the thermal conductivity of NdMnO and TbMnO due to 4f crystal-field excitations
We present measurements of the thermal conductivity and the thermal
expansion of NdMnO and TbMnO. In both compounds a splitting of
the multiplet of the ion causes Schottky contributions to
. In TbMnO this contribution arises from a crystal-field splitting,
while in NdMnO it is due to the Nd-Mn exchange coupling. Another
consequence of this coupling is a strongly enhanced canting of the Mn moments.
The thermal conductivity is greatly suppressed in both compounds. The main
scattering process at low temperatures is resonant scattering of phonons
between different energy levels of the multiplets, whereas the complex 3d
magnetism of the Mn ions is of minor importance.Comment: 9 pages including 6 figure
Path integral quantization of electrodynamics in dielectric media
In the present paper we study the Faddeev-Popov path integral quantization of
electrodynamics in an inhomogenious dielectric medium. We quantize all
polarizations of the photons and introduce the corresponding ghost fields.
Using the heat kernel technique, we express the heat kernel coefficients in
terms of the dielectricity and calculate the ultra violet
divergent terms in the effective action. No cancellation between ghosts and
"non-physical" degrees of freedom of the photon is observed.Comment: 10 pages, Latex, submitted to J.Phys.A, revised (a misprint in the
bibliography
Intrinsic decoherence and classical-quantum correspondence in two coupled delta-kicked rotors
We show that classical-quantum correspondence of center of mass motion in two
coupled delta-kicked rotors can be obtained from intrinsic decoherence of the
system itself which occurs due to the entanglement of the center of mass motion
to the internal degree of freedom without coupling to external environment
Scheme for generating entangled states of two field modes in a cavity
This paper considers a two-level atom interacting with two cavity modes with
equal frequencies. Applying a unitary transformation, the system reduces to the
analytically solvable Jaynes-Cummings model. For some particular field states,
coherent and squeezed states, the transformation between the two bare basis's,
related by the unitary transformation, becomes particularly simple. It is shown
how to generate, the highly non-classical, entangled coherent states of the two
modes, both in the zero and large detuning cases. An advantage with the zero
detuning case is that the preparation is deterministic and no atomic
measurement is needed. For the large detuning situation a measurement is
required, leaving the field in either of two orthogonal entangled coherent
states.Comment: Accepted in J. Mod. Opt.; 12 pages; Replaced with revised version.
Extended discussion of experimental realizations, earlier studies in the
field and on the frequency dependence in the adiabatic eliminatio
Dilatonic current-carrying cosmic strings
We investigate the nature of ordinary cosmic vortices in some scalar-tensor
extensions of gravity. We find solutions for which the dilaton field condenses
inside the vortex core. These solutions can be interpreted as raising the
degeneracy between the eigenvalues of the effective stress-energy tensor,
namely the energy per unit length U and the tension T, by picking a privileged
spacelike or timelike coordinate direction; in the latter case, a phase
frequency threshold occurs that is similar to what is found in ordinary neutral
current-carrying cosmic strings. We find that the dilaton contribution for the
equation of state, once averaged along the string worldsheet, vanishes, leading
to an effective Nambu-Goto behavior of such a string network in cosmology, i.e.
on very large scales. It is found also that on small scales, the energy per
unit length and tension depend on the string internal coordinates in such a way
as to permit the existence of centrifugally supported equilibrium
configuration, also known as vortons, whose stability, depending on the very
short distance (unknown) physics, can lead to catastrophic consequences on the
evolution of the Universe.Comment: 10 pages, ReVTeX, 2 figures, minor typos corrected. This version to
appear in Phys. Rev.
Confounding conventional wisdom: political not principled differences in the transatlantic regulatory relationship
The transatlantic complaints over hormone-treated beef and genetically modified organisms before the World Trade Organisation (WTO) seem to confirm two separate but related conventional wisdoms about the transatlantic economic relationship: that it is highly conflictual and that many of the conflicts are rooted in profoundly different approaches to regulation. This article argues that neither of the two conventional wisdoms is accurate. Rather, it contends that they are products of two, compounding analytical shortcomings: one methodological, one empirical. The methodological shortcoming takes the form of an implicit selection bias. While WTO complaints are high profile they are rare and extreme examples; it is, therefore, unsound to generalise from them to the regulatory relationship as a whole. The empirical shortcoming has to do with neither the beef hormones nor the GMO dispute demonstrating what it is purported to. The article thus serves as a cautionary tale about the dangers of relying on obvious cases and the need to question whether evidence really does support a prevailing popular narrative
Conceptualizing pathways linking women's empowerment and prematurity in developing countries.
BackgroundGlobally, prematurity is the leading cause of death in children under the age of 5. Many efforts have focused on clinical approaches to improve the survival of premature babies. There is a need, however, to explore psychosocial, sociocultural, economic, and other factors as potential mechanisms to reduce the burden of prematurity. Women's empowerment may be a catalyst for moving the needle in this direction. The goal of this paper is to examine links between women's empowerment and prematurity in developing settings. We propose a conceptual model that shows pathways by which women's empowerment can affect prematurity and review and summarize the literature supporting the relationships we posit. We also suggest future directions for research on women's empowerment and prematurity.MethodsThe key words we used for empowerment in the search were "empowerment," "women's status," "autonomy," and "decision-making," and for prematurity we used "preterm," "premature," and "prematurity." We did not use date, language, and regional restrictions. The search was done in PubMed, Population Information Online (POPLINE), and Web of Science. We selected intervening factors-factors that could potentially mediate the relationship between empowerment and prematurity-based on reviews of the risk factors and interventions to address prematurity and the determinants of those factors.ResultsThere is limited evidence supporting a direct link between women's empowerment and prematurity. However, there is evidence linking several dimensions of empowerment to factors known to be associated with prematurity and outcomes for premature babies. Our review of the literature shows that women's empowerment may reduce prematurity by (1) preventing early marriage and promoting family planning, which will delay age at first pregnancy and increase interpregnancy intervals; (2) improving women's nutritional status; (3) reducing domestic violence and other stressors to improve psychological health; and (4) improving access to and receipt of recommended health services during pregnancy and delivery to help prevent prematurity and improve survival of premature babies.ConclusionsWomen's empowerment is an important distal factor that affects prematurity through several intervening factors. Improving women's empowerment will help prevent prematurity and improve survival of preterm babies. Research to empirically show the links between women's empowerment and prematurity is however needed
A inserção do Brasil no mercado mundial de alumínio: incorporando contribuições da Ecologia Política para a Saúde Coletiva
O presente artigo discute a inserção do Brasil no mercado mundial de alumínio a partir dos referenciais teóricos da ecologia política, da economia política do território e da saúde coletiva. A conjuntura contemporânea da economia mundial tem sido pautada pela desregulamentação e liberalização, característicos do ideário neoliberal propalado pelas nações centrais. A maior participação do Brasil nesse mercado tem sido realizada a partir do aumento da produção e exportação de commodities agrárias e metálicas, como o alumínio. Nesse sentido, a partir dos paradigmas da ecologia política, o texto propõe uma análise das consequências socioambientais, assim como sobre novas territorialidades que se produzem e reproduzem dentro de uma lógica econômica que privilegia as nações centrais. Do mesmo modo, procura-se compreender os dilemas da saúde coletiva sob uma perspectiva holística e integradora na qual se articula aos modelos de desenvolvimento econômico. Percebe-se que a produção e exportação de alumínio primário, apesar de apresentar um valor agregado maior, esconde um conjunto difuso de impactos que afetam o ambiente e a saúde coletiva
Dwelling, house and home: towards a home-led perspective on dementia care
“Home” is well known from everyday experience, plays a crucial role in all kinds of narratives about human life, but is hardly ever systematically dealt with in the philosophy of medicine and health care. The notion of home is ambiguous, is often used in a metaphorical way, and is closely related to concepts such as house and dwelling. In this paper the phenomenon of home is explored by means of some phenomenological writings of Heidegger, Bollnow, Bachelard and Levinas. Common in their views is that being at home and dwelling mean something more fundamental than an activity we do along with other activities, such as working and travelling. Dwelling, building a house and being at home are fundamental aspects of human existence. Being human is dwelling. While exploring the relevance of this phenomenological perspective for medical theory and practice, the focus is on the care of people suffering from dementia
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